This adds PostConstructionCallbackTrait which can be used to get a
callback that is executed right after an object instance is created.
This can be useful for hooks that require to be able to call into
virtual methods.

Bug: chromium:1074061
Change-Id: Idd5ef677fed291bcba81b9a47f2932c9bb5832b4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2179385
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67557}